Details

Date

1813

Author

Brewster

Contribution

Suggested immersion of front element of objective in the fluid in which the object is placed.

Reference

Bradbury

Notes

This would improve color correction and keep object from drying out. Published his ideas in book, 1813, but made the suggestion in 1812. The achromatic effect was obtained by immersing the several spaced (not cemented) lenses of the front element in vegetable oil, so that the oil between these convex lenses acted as liquid "biconcave lenses."